implement gunicorn WSGI

dockerfile

@@ -1,31 +1,23 @@
 # Dockerfile
 FROM python:slim
 
-# Set work directory
 WORKDIR /app
 
-# Install PostgreSQL client
+# Only what you actually need (ffmpeg kept for video/thumbs)
 RUN apt-get update && \
-    apt-get install -y postgresql-client ffmpeg && \
-    apt-get clean && \
+    apt-get install -y --no-install-recommends ffmpeg && \
     rm -rf /var/lib/apt/lists/*
 
-# Copy project files
+# Install deps first for better layer caching
+COPY requirements.txt .
+RUN pip install --upgrade pip && pip install --no-cache-dir -r requirements.txt
+
+# Copy the rest of the app
 COPY . .
 
-# Install dependencies
-RUN pip install --upgrade pip && pip install -r requirements.txt
-
-# Copy and prepare entrypoint script
+# Entrypoint controls migrations, background worker, and Gunicorn
 COPY entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh
 
-# Set environment variables
-ENV FLASK_APP=run.py
-ENV FLASK_RUN_HOST=0.0.0.0
-
-# Expose port
 EXPOSE 5000
-
-# Use entrypoint script
 ENTRYPOINT ["/entrypoint.sh"]